In one conventional form of electrode, the electrode comprises a metal element having a suitable current-carrying wire connected thereto. The electrode illustrative may be disposed in an electrolytic bath, soil, etc. In such an application, when direct current is applied to the electrode, ionic conduction through the grounding medium relative to the electrode is effected.
Chemical changes occur at the boundary between the electrode and the surrounding medium. Illustratively, conventional uses of such electrodes are in electric plating, electric metallurgy, treatment of soils, such as to remove disease bacteria or microorganisms therefrom, electrolytic plating operations, etc.
In Japanese laid-open patent application Nos. 127127/1978 and 259533/1987, such electrodes are utilized in soil for removing specific diseased bacteria and microorganisms.
The use of metal or graphite electrodes presents the serious problem in the lack of durability due to oxidation of the surface of such electrodes, where the electrodes are used as anodes. Such oxidation causes contamination of the electrolyte and further causes disintegration of the anode, requiring replacement thereof in normal use.
Further, it is difficult to manufacture such metal or graphite electrodes in other than extremely simple shapes due to the high hardness thereof.
One attempted solution of the problem is to plate the electrodes with noble metal, such as platinum, gold, etc. Such attempted solution is not fully satisfactory because of the high expense thereof.
Graphite electrodes are subject to such oxidation, as well as the metal electrodes.
Further, soil particles adhering to the surface of the electrodes, or gas generated by the electrolytic reaction at the electrode cause a serious problem in the reduction of the current flow.